Field of the Invention
The present invention relates generally to bore masking devices and more specifically it relates to a bore masking system for effectively protecting the interior surface of a bore during all phases of the painting process.
Description of the Related Art
Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field.
Painting of objects with bores is done every day. The bore may be comprised of a circular cross sectional area having a first open end and a second open end. It can be appreciated that the bore may have only one open end with a second closed end. The bore may have a smooth interior surface or a non-smooth interior surface (e.g. a plurality of splines or grooves). The bore may also include a keyway and/or rounded surface openings.
Examples of objects that are painted having at least one bore includes parts for tractors, tractor loader hinges, frame parts, support arms, hinges, joints, pulleys, sprockets, and other structures where a pin (or other elongated object) is later inserted through the bore after painting the object. While the objects typically painted are constructed of metal, the objects may be constructed of non-metal materials. It is important that the interior surface of the bore is not damaged or contaminated before, during or after the painting process. Painting of objects typically has three phases: (1) cleaning the object of undesirable substances, (2) applying paint to the object and (3) curing the paint.
Cleaning of the object includes but is not limited to abrasive blasting (e.g. sandblasting, bead blasting, shot blasting, sodablasting, wet abrasive blasting), spray washing, dip washing or otherwise applying a chemical cleaner to the object. Painting of the object may be accomplished using various types of painting processes including but not limited to liquid painting (e.g. spray painting), powder coating, e-coating (electrophoretic deposition), electroplating, plating and anodizing. Curing of the paint includes but is not limited to heating in a bake oven, fans or ambient air drying.
It is important to protect the bore of the object during the cleaning process from being directly contacted with the cleaning material, particularly when abrasive blasting processes such as sandblasting are used, to prevent the interior surface of the bore from being physically damaged. It is further important to protect the bore of the object during the actual painting portion of the painting process to prevent paint from being applied to the interior surface of the bore. While paint may be applied by spraying a liquid paint with spray nozzles, paint may also be applied by dipping the object within a dip tank containing the paint. Finally, it is important to protect the bore of the object during the curing of the paint so that paint applied to the exterior of the object does not accidentally drip into the bore prior to hardening.
To protect the bore of the object during the painting process, users must mask the bore with a masking product to prevent damage to the interior surface of the bore. Conventional masking products used to mask a bore include silicone plugs (tapered and non-tapered), silicone flange caps, EDPM pull plugs, masking tape, flexible silicone foam cord and silicone tubing. One of the problems with conventional masking products is that they typically are sized to fit within a specific diameter and/or length of bore thereby requiring a painter to purchase various sizes of the masking products for different diameters and/or lengths of bores. Tapered silicone plugs do exist however they are limited to a range of diameters and can leave the distal end of the bore exposed if not properly used. Another problem with conventional masking products is they are not suitable for allowing a hook or other support member to extend through the bore to support the object during the cleaning, painting and/or curing processes. A further problem with conventional masking products is that they may potentially maintain a conductivity between the hook and the part to be painted. Another problem with silicone plugs is that they can be difficult to remove from the bore after the paint is cured. Another problem due to the high cost of silicone, returnable systems must be put into place and managed which can include cleaning of the plug as paint sticks to them and flakes off causing defects if used again and not cleaned which also creates a mess of paint flakes for the user during handling.
One type of masking product recently used is compressed cardboard rolled up to be inserted into the bore. Recently, flat and planar resilient sheets of non-metal gasket material have been used as a masking product to provide a solution to the inherent problems with conventional masking products. In particular, the gasket material is received by the painter in sheet form (e.g. 5×7 inches) and the painter manually rolls the sheet of gasket material into a tubular sleeve that is then inserted into the bore and then allowed to expand to the size of the bore to protect the interior surface of the bore. Another example of a gasket material that has been used as a masking product for the past couple of years is VB-72 PRO-FORMANCE®/MICROPORE® manufactured by Interface Solutions, Inc. in Lancaster, Pa. While the sheets of gasket material rolled into a tubular sleeve solve the problems experienced by the older masking products discussed above, a new problem was encountered wherein the gasket material absorbs liquids during the cleaning process. After the gasket material absorbs the liquid, the gasket material loses some of the resiliency needed to remain snugly within the bore. Once the gasket material has absorbed a portion of liquid and loses its resiliency, the gasket material may sag exposing portions of the bore or may completely fall out of the bore. In addition, the gasket material also absorbed paint creating similar problems and also creating the problem of when the paint is cured with baking that the paint absorbed by the gasket material is cured to the interior surface of the bore making a clean removal of the gasket material difficult.
Because of the inherent problems with the related art, there is a need for a new and improved bore masking system for effectively protecting the interior surface of a bore during all phases of the painting process.